Gross Margin vs. Net Profitability: Why Your Customer Profitability Numbers Are Probably Wrong

If you measure customer or product profitability based on gross margin, you are almost certainly making decisions with incomplete information. It is one of the most common and most costly oversights in business management, and it affects companies of every size and sector.

Gross margin tells you what you earn after direct costs. It does not tell you what it actually costs to serve a customer, fulfil an order, or support a product through its lifecycle. That gap between gross margin and net profitability is where the real story lives.

The Problem with Gross Margin as a Profitability Measure

Gross margin is straightforward to calculate: revenue minus cost of goods sold. For a manufacturing company, that means raw materials and direct labour. For a distributor, it means the purchase cost of goods. Simple, clean, and dangerously misleading.

Here is why. Two customers can buy the same product at the same price, generating identical gross margins, while one is highly profitable and the other is destroying value. The difference lies in everything that happens after the sale is recorded:

Order patterns: Does the customer place one large order per month or twenty small orders per week? Each order consumes warehouse picking time, packing materials, shipping coordination, and invoicing effort.

Delivery requirements: Does the customer accept standard delivery, or do they require express shipping, specific delivery windows, or multiple drop-off points?

Payment behaviour: Does the customer pay on time, or does your accounts receivable team spend hours on follow-ups and reminders?

Returns and complaints: How often does the customer return products or raise service issues that consume your team’s time?

Custom requirements: Does the customer need special packaging, labelling, documentation, or reporting that other customers do not?

None of these costs appear in a gross margin calculation. Yet collectively, they can easily represent 15 to 30 percent of revenue for high-maintenance customers.

A Distribution Company Example

Consider a mid-sized distribution company that analysed its customer base beyond gross margin for the first time. With over 2,000 active customers and thousands of SKUs, management had always segmented customers by revenue and gross margin. Their top 50 customers by revenue were treated as the most important accounts, receiving the best pricing and the most attention.

When the company applied a cost-to-serve analysis, the results were eye-opening. Several of their “top” customers, those with the highest revenue, were actually among the least profitable when all service costs were allocated. One customer, ranked 8th by revenue, dropped to the bottom quartile in net profitability. Why? They placed frequent small orders, required rush deliveries twice a week, returned products at three times the average rate, and demanded custom reporting that consumed hours of analyst time each month.

Meanwhile, a mid-sized customer ranked around 120th by revenue turned out to be in the top 20 for net profitability. They ordered predictably, accepted standard delivery, paid promptly, and rarely required after-sales support.

Understanding Cost-to-Serve

Cost-to-serve is the total cost of all activities required to serve a specific customer, from order processing through delivery and post-sale support. It includes:

Commercial costs: Sales visits, account management, quotation preparation, and contract negotiation.

Order processing costs: Order entry, credit checking, picking, packing, and shipping.

Logistics costs: Transportation, route planning, special handling, and returns processing.

Administrative costs: Invoicing, collections, dispute resolution, and customer-specific reporting.

When you subtract cost-to-serve from gross margin, you get a much more accurate picture of customer net profitability. And that picture almost always contains surprises.

What to Do with the Data

The point of customer profitability analysis is not to fire unprofitable customers. It is to make informed decisions about how to manage each relationship. Typical actions include:

Re-pricing: Adjusting prices or fees for customers whose cost-to-serve is significantly above average.

Service level restructuring: Offering different service tiers that align with the cost of delivery. Customers who want premium service should pay for it.

Operational improvement: Identifying process inefficiencies that inflate cost-to-serve across the board.

Strategic focus: Directing sales and marketing efforts toward customer profiles that are genuinely profitable, not just high-revenue.

Minimum order policies: Establishing thresholds that prevent the accumulation of tiny, high-cost orders.

Moving Beyond Gross Margin

Gross margin remains a useful metric for understanding product economics and negotiating with suppliers. It should not be abandoned. But it should never be the final word on profitability.

Companies that implement cost-to-serve analysis consistently report the same finding: their assumptions about which customers and products are most profitable were significantly wrong. Not slightly off. Significantly wrong.

The methodology exists. The data, in most cases, is already available in your systems. The only barrier is the decision to look beyond the gross margin line and see what your business actually costs to operate at the customer level.

By Miguel Guimaraes, Partner at Cost and Profitability Consulting and Co-Founder of CostCTRL